So called Elvstrom-type bailers (produced by Andersen and others) are commonly employed in sailboats. Such bailers are fixed in an aperture formed in a boat bottom, and employ a wedge-shaped venturi having an opening facing the rear of the boat on the outside of the boat hull to permit outflow of water at high speed forward travel. The flow of deflected water draws water from inside the boat as long as the boat is moving through the water at a fairly rapid speed. A flap, open during rapid speed travel, acts as a non-return valve, closing when the boat is stationary in the water or moving too slowly for outflow. The bailer can be closed so that it is flush with the surface of the hull, completely sealing it from incoming water and eliminating drag from the bailer.
A drawback in existing Elvstrom-type bailers is that there is limited area from which water can drain. Water can only drain from the gated portion at the back of the wedge, which is about 50% of the rear vertical surface.
Another drawback in such bailers is that they cannot be easily adjusted to different levels. Such bailers are typically used in either the fully open position—allowing water drainage while inducing a significant amount of drag on the boat, or fully closed—eliminating the extra drag, but allowing no drainage. The bailers must be opened at least 50% to allow the gate to open and draining to begin. Between 50% and 100% open, it is very difficult to judge how far the bailer is open, thus making it impractical to adjust the amount of bailing needed.
Thus there is a need for a bailer which provides a higher ratio of draining speed (bailing) to induced drag, and which is adjustable at various levels to vary the draining rate and induced drag.